Before a heart-lung machine can be used, it has to be prepared such that the patient can be connected quickly and safely to the system. This requires a machine in which the blood-conveying components are vented (also called “de-aired”) by a filling liquid. The filling procedure is also called “priming” of the machine.
Air inclusions or released quantities of air can, during later use on the patient, cause air embolisms and, in the worst case, death.
Components and hose systems in conventional heart-lung machines are hitherto for the most part prepared for use by being filled and vented manually. The preparation is performed, for example, by partial filling of components, manual clamping of hose lines, “beating out” of air bubbles, tilting of components, or cyclical driving of the blood pumps. Components such as hoses, connectors and reservoir have to be vented in addition to components such as oxygenator, filter and blood pumps. When venting a conventional heart-lung machine by filling it, the filling procedure has to be carried out by experts (cardio technicians). This applies also to regular operation. By means of the manual interventions described above, the system is made ready for use. In some systems, the filling procedure takes place semi-automatically but nevertheless requires trained personnel and/or cardio technicians, who perform the filling procedure. In the semi-automatic method, the operator partly has to clamp hoses, initiate pump actions, etc.
Generally, these manual interventions are complicated and cost-intensive in terms of personnel. These manual interventions are also susceptible to error and are difficult to document.
The use of the manual interventions, particularly in emergency situations, causes difficulties for the patient, who is reliant on a rapid start-up of the heart-lung machine. In addition, the costs and the time that are needed for the intervention increase.
The European patent specification EP 1,661,592 B1 by Lifebridge Medizintechnik AG describes a portable heart-lung machine with semi-automatic filling. These portable heart-lung machines consist of a base station and of a control module with attached patient module. EP 1,661,592 is herewith incorporated by reference in its entirety and for all purposes. The patient module contains the blood conveying components and is disposed of after use by separation from the control module. The bloodconveying components include the blood pump, in the form of a centrifugal pump, a reservoir with filling level sensors, an arterial filter, an oxygenator, various connecting hoses and bypasses, and also sensors for detecting air and gas bubbles and for measuring pressure and flow.
In the portable heart-lung machine that is described in EP 1,661,592 B1, the components are filled and vented by manual rotation of the complete unit through 90° to a filling position. In the filling position, an automatic method is then initiated that permits filling. After the filling procedure, the unit is rotated back through 90° to a filled operating position. By the rotation to the operating position and by a method for automatic detection and elimination of air bubbles, the system is brought to the operating state.
However, for the rotation movement during venting, an additional mechanical rotary holder is needed in order to move the control module with the patient module from the operating position to the filling position and back again.
Moreover, in the manual and also in the semi-automatic systems, there is the danger of air inclusions being overlooked or undetected despite visual inspection of the components.
US Patent application number US2008/171960 of the same applicant as the present applicant, which hereby is incorporated by reference in its entirety for all purposes, an apparatus is disclosed for making extracorporeal blood circulation available, in a particular a heart-lung machine, comprising a venous connection and an arterial connection, between which a blood reservoir, a blood pump and a bubble detector for the detection of air bubbles are provided, with, downstream of the bubble detector, an arterial line leading to the arterial connection via an arterial clamp and a bypass leading via a bypass clamp back into the blood reservoir which is connected to a pump extracting air from the blood reservoir. In addition, a method is disclosed of operating such an apparatus. In WO 2005/065743 an EXTRACORPOREAL BLOOD CIRCUIT PRIMING SYSTEM AND METHOD are disclosed. A disposable, integrated extracorporeal blood circuit is disclosed that is employed during cardiopulmonary bypass surgery performs gas exchange, heat transfer, and microemboli filtering functions. A manual priming method is described.
Hence, there is a need to provide for improved priming methods and systems allowing for such improved priming. Advantageously, the priming should be done automatically.
Therefore, an aim of the disclosure is to ensure that a heart-lung machine can be vented fully automatically by filling, without input by the operator, and thus made ready safely for use. No manual interventions for venting should be performed on the components in the patient module between starting up the machine (initialization, manual attachment of various hose lines and manual attachment of the filling liquid) and the attachment to the patient. Moreover, the time needed for the venting method is intended to be further reduced by eliminating the previously required rotation of the base module for the venting procedure. Thus, the system is made rapidly available for use, especially for short-term emergency use.
It is therefore desirable to make available a method for preparing and venting a heart-lung machine in the form of a portable heart-lung machine, which method can take place without intervention of the operator. It is desirable in particular that, after the attachment of the filling liquid and the attachment of the table line, the filling procedure should be started manually and proceed fully automatically.
Components that are difficult to vent, such as a blood pump and an arterial filter, are preferably to be made available in such a way that, in the venting method, the air in the components can advantageously be purged and escape. Documentation of the venting procedure should be made possible by the components and method.